Following the rapid growth in computing power and in particular for portable electronics, the specifications and restrictions on the power delivery have been significantly tighten to assure compact, light, energy efficient, and economical power sources. Efforts to accommodate these challenges range from the selection of the power devices, frequency of operation, through new topologies for switch-mode power supplies (SMPS), controller types and others. In recent years, the technology for on-chip integration of a power device with its controller and further advancements for co-packaging of reactive components (e.g. inductors, capacitors) have enabled a new generation of compact, efficient and economical Voltage Regulator Modules (VRMs).
In the worldwide trend of integration, digital design is predominant with several advantages such as convenience of the design, flexibility, scalability, and potential performance improvements. However, in power electronics and particularly in VRM applications, analog-oriented integration and analog controllers lead the trend. The main reason for use of analog components is that wide control bandwidth can be obtained without a significant penalty in the die area or power consumption. In order for a digital controller to be attractive and compete with an analog one, a low supply voltage process is preferred. This however introduces a tradeoff for a monolithic design, where die area for power devices is rather large, especially for inputs that are over 5V. The main limiting factor of digital technology in integrated power processing applications is therefore that controller architectures have not been optimized to the operation of the SMPS, but uses rather generalized cores to execute very specific tasks. It would be extremely beneficial if a digital controller would be specifically tailored to the set of tasks required by the SMPS and realized through a simple digital design flow, with competitive sizing, on a similar process of the power devices.
It is therefore an object of present invention to provide architecture of a fully digital of a VR controller.
It is another object of the present invention to provide a fully digital auto-tuning ACM controller that follows the classical two-loop ACM design with an all-digital outer voltage and inner current loops.
Other objects and advantages of this invention will become apparent as the description proceeds.